Office (OOXML) malware analysis — malicious · d775e8cf2323df52

MALICIOUS

Office (OOXML)

1.03 MB Created: 2021-04-28 21:02:36 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2021-06-17

MD5: 929327c1d7e206d061dce6504d68b026 SHA-1: bcb0191f90efdd79703e19a6f91bede00e00373f SHA-256: d775e8cf2323df52d78772f5528ee300aa3b9d1dc707684d8913c90624442328

142 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The file is a malicious Microsoft Excel document containing an embedded OLE object, specifically an Equation Editor object. Heuristics indicate this object exploits CVE-2018-0798, a vulnerability in Equation Editor, to execute a payload. The embedded object's Ole10Native stream exhibits high entropy and anomalous characteristics, suggesting it contains malicious code. The primary attack vector is likely spearphishing attachment.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/rWoLuU.lC contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY

Embedded Equation Editor OLE data contains anomalous native stream bytes consistent with a CVE-2018-0798-style Equation Editor exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like, but it does not match the exact public matrix-overflow byte signature.
Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY

Embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is an exploit-shaped Equation/OLE payload container seen in malicious OOXML samples. It is not assigned to a specific CVE unless the MTEF/Equation Native primitive also matches.
Embedded OLE object medium OOXML_OLE_OBJECT

Document contains an embedded OLE object
Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE

One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`ooxml_oleobject_00.bin`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/rWoLuU.lC	1333248 bytes
SHA-256: `620fa7a09f1984efb484652859a4696cd7f686301214b0bb035943c09d21580e`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.74, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin`	ole-package	OOXML xl/embeddings/rWoLuU.lC Ole10Native stream: Ole10Native	1320429 bytes
SHA-256: `0507fd8e8274198a805756b4578f7e8489ad3c3cf8423500e55bb9b04ca869e4`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.72, consistent with packed or encrypted content.

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